The Vegetation of Western Australia. 
xlv. 
In the western area of its distril^ution, between the 200 and 150 mm. 
isohyets the arborescent species are few, comprising three principal species 
— Eucalyptus salmonophloia, E, lonqicornis, and E. sahfbris, but to the east 
there is a greater admixture of the species, at least a dozen trees entering 
into the composition. Within the South-West Province, i.e., as far as Mer- 
redin, there is a comparatively rich development of shrubs, amongst which 
Acacia and Proteaceae are predominant, but to the east of the provincial 
boundary there is a notable development of Myoporaceae and Chenopo- 
diaceae, the former being shrubs 3-5 metres high, mostly with an ephedra- 
like habit, while the Acaciae become fewer, and the woodland undergrowth 
more sparse and more and more given over to Chenopodiaceous species. 
Where the soil becomes more alkaline, the Chenopodiaceae become increas- 
ingly important, often associated with Amarantaceae and shrubby Compositae. 
Tliis is particularly the case to the east and south of Widgiemooltha, where 
the grey-bush (Cratystylis conocephala) assumes great physiognomic im- 
])ortance, and Melaleuca becomes more common, while the tree species be- 
come more social than in any other formations, but all have more or less 
the same characteristics, so that field recognition becomes difficult. For 
example, at Norseman there are at least fifteen Eucalyptus species in close 
association. 
The sclerophyllous woodland formations are everywhere limited by the 
edaphic factor — ^nowhere do they occur on sand — -and typically they inhabit 
the alluvial depressions, the broad red-soil plains, or finally the alkaline soils 
of the “ lake ” country. The last-mentioned type is to be found principally 
in the Lake Brown-Yilgam country, southwards to Kondinin and Lake King, 
while to the east, there is a broad area of the formation between Widgiemooltha 
and Dowak, extending some distance westwards, and eastwards almost to 
Balladonia. The soil is more or less saline, and the Eucalyptus species are 
in the main different from those of the red clay soils. Eucalyptus Brockwayi 
and E. leptophylla take the place of E. salmonophloia ; Eucalyptus campaspe 
the place of E. salubris, and E. Flocktoniae and E. oleosa var transcontinentalis 
the place of E. longicornis. Besides the low undergrowth of Chenopodiaceae, 
there are larger shi'ubs, such as Melaleuca pauperifiora and M, quadrifaria, 
known as Boree ”, and extensive tracts of Cratystylis conocephala, as well 
as several broom-like species of Eremopkila, Where the red clay soil woodland 
occurs there is a notable reduction in Chenopodiaceous plants, and the under- 
growth is lower and of a more uniform stature. Acacia and Myrtaceous species 
predominate. 
A curious fact which is worth mentioning here is that with the increase 
of summer rains to the south of the Coolgardie district, and in the Eyre district, 
the grasses become of increasing importance. For example, already at Dundas, 
grasses are important in the undergrowth of the open woodland, and between 
Mount Holland and Dowak it is not uncommon to find, after burning, especially 
with summer rains, areas of woodland country carrying a fairly dense covering 
of grass. This state of things represents a succession in the woodland which 
appears to be only temporary, for ultimately the Eucalyptus seedlings grow 
into trees and shrubs, and the country reverts to woodland. At the same time, 
areas occur which appear to be permanently clothed with grass ; these small 
areas represent natural fields in the woodland, and appear to be a permanent 
feature of the southern sclerophyllous woodland zone. The best known 
example is perhaps Grasspatch, an area of a few hundred acres, which in its 
virgin condition consisted entirely of grasses, closely surrounded by the wood- 
land. Other examples of these grassy “ oases ” occur between Norseman 
and Balladonia, but are mostly little more than a few acres in extent. They 
